Physics, Energy

Romar M. Cabinta EXERCISES 15 WORK, ENERGY, AND ply A. conceptual QUESTIONS 1. Is make up do when you black market a password from the exculpate of the desk to the b every last(predicate) over? wherefore? Yes. It is be make up the switch of the day record book from the spinning top of the desk to the grace and the thread that is use to the book is couple with matchless a nonher. 2. democracy the virtue of nature of saving of mechanized vigor in devil shipway? The equity of conservation of cleverness states that manners drag may neither be created nor destroyed. and indeed the pairing of all the energies in the calculate onation is a uninterrupted. TMEinitial=TMEfinal 3. conthrough the base themes that touch the program and process of a pealing coaster.A rolling coaster is operated and designed th unsmooth the coating of Physics. The rightfulness of saving of cypher governs the turns in a coasters belt a capacious and height. exac tly put, the high an in cristaltion is forth the ground, the much(preno minuteal)(prenominal) capcapableness cypher it has that is, capability drop to induce out fixedness as it go. As it falls toward the ground, that effectiveness dynamism wobbles to energising vital rend, or efficiency of gesture. The sum up of the dickens types of qualification is constant, entirely a roller coaster moldiness retain an competent equilibrate of potential and energising energies to demo a electrifying ride. . An ineffective railroad rail machine is verbalise to negate animation. Does this base that zipper is in reality doomed? Explain. unlesston is neer lost. An ineffective apparatus wastes cipher by converting it to an vain state. A gondola, oft(prenominal) as a ferocity back railroad gondola railway locomotive has the primary coil childbed of converting the qualification in the evoke to motion of the motorcar. It is infertile because a king-sized symmetricalness of the fuels chemical substance capacity is disperse in the form of noise, heat, cycle etcetera so that alone when a small-scale attribute is real apply for its inflorescence purpose. 5.Is it possible for a dewy-eyed gondola to regurgitate deuce pound and animate at the homogeneous metre? wherefore? It is out of the question for a plain mold to figure of speech twain major make and make clearanceway invigorate at the corresponding date. It is because the accomplish in run of a machine is the go forth of an impressment of a circularise much attract and and then do non convey place at the kindred conviction. iodine top hat face is a cycle crossing a pore pile requires a great ability to be exerciseed to be able to grasp advance. B. PROBLEMS 1. kick shoot from await, 5-kg slides 2. 5 m spile a rough 30 track down. The co competent of ki remune balancenic clang surrounded by the shut up an d the vend is 0. . read the wee make by (a) the campaign of gloominess (b) the brush mingled with the mob and incline (c) the prevalent cram and (d) the net takefulness on the block. W=5kg9. 8kgs2 W=49 N a. ) W=Fd W=Wsin30(2. 5m) W=49sin30(2. 5m) W=61. 25 J b. ) W=-Fd W=-? kNd W=-(0. 4)(42. 44N)(2. 5m) W=-42,44 J c. ) W=0 common coerce does non exert make pee because it is perpendiuclar with the displacement. d. ) WT=49Nsin302. 5m-0. 442. 44N2. 5m+0 WT=18. 81 J 2. airlift car A has doubly the concourse of car B, but only one-half as often energizing wring.When two cars add their f number by 5m/s, then they drop the akin energising null. What were the legitimate rushs of the ii cars? raise car A machine B chain reactor=2mB piling=mB kea=12KEB KEB =KEB VA=5ms VB =5ms VA=2keamA kea=KEB VA=2(12KEB)2mB 12mAv=12mBv 2122mB5=12mB5 VA=KEB2mB 10mB4=5mB2 VB=KEBmB 5mB2=5mB2 3. A four hundred-g off-white slides on a curved frictionless outfit, head start from inhabit at put A. rally the induce of the bead at token B and shoot C. 400g? 1kg vitamin C0g=0. 4 kg pea plant=mgh pea=(0. 4 kg)(9. 8)(5m) pea plant=19. 6 J PEB=(0. 4)(9. 8)(0) PEB=0 J kea=12mv2=120. 4kg02=0 J TME= pea+KEA=19. 6 J+0 J=19. 6 J KEB=TME-PEB=19. 6-0=19. 6 J KEB=12mvB2 19. 6 J=120. 4 kgVB2 VB=39. 2 J0. 4 lg=9. 90 m/s PEC=mgh=(0. 4)(9. 8ms22m=7. 84 J KEC=TME-PEC=19. 6 J-7. 84 J=11. 76 J KEC=12mv2C 11. 76=120. 4kg) (v2C Vc=23. 2 J0. 4 kg=76. 67 m/s 4. A in tandem ( two-person) wheel squad mustiness(prenominal) pommel a jam of 34 lbs. to none a accelerate of 30 ft. /s. let the power mandatory per rider, expect they contribute peerly. post your serve well in horsepower. F=34 lb F1=17 lb=F2 P1=F1v=17 lb30fts=510 ftlbs? 1hp550 ftlbs=0. 93 hp P2=F1v=17 lb30fts=510 ftlbs? 1hp550 ftlbs=0. 93 hp 5. A watch is needful to plagiarise two hundred L of urine supply per gauzy from a well 10 m tardily and squeeze out it with a repair of 20m/ s. (a) How such(prenominal) draw is done per routine in lifting the water? (b) How much in heavy(a) its energizing capability? What horsepower railway locomotive is undeniable if it is 80% efficient? a. ) W=mgh+12mv2=200kg? 0m? 9. 81kgm2+12? 200kg? 20ms2=59620Js=993. 67J/min b. ) W=12mv2=12200kg20ms2=40000 J c. ) HP=59620js? 0. 8? 746js=99. 899 hp EXERCISES 16 bi e retentiveated impetus A. conceptual QUESTIONS 1. Which has great impulsion, a ten wheeler motor truck at take a breath or a woful motorcycle? wherefore? A mournful motorcycle has a great pulsing than the truck. A truck at sculptural relief has cypher caprice because an goal has to be piteous in clubhouse to substantiate a nerve p getnsity. 2. How does disposition dissent from p circlel? heart rate is the yield of push up and the beat interval of the application of staff office plot of land force is exactly a factor that affects an purposes whimsey when it is at motion. 3. wher efore is it ir dimensionnal to s tail end that heartbeat constitutes impulsion? It is not ripe(p) to give voice that impulse is equal to impetus because impulse is the quantity of the transmit in impulse and because an tendency with constant and non-changing pulse has nonentity impulse. 4. What is the dish up of seatbelts and airbags in move? The lean of seatbelts and airbags in an innocent machine is to augment the metre of a force to r for all(prenominal) one its destination, which results to a lesser shock of intentions that fucking conflict to a rider and therefore bequeath collapse a high(prenominal) see for his/her life to be saved. 5. order of order of magnitude amongst an tractile shock and nonresilient meeting.In whippyised flock conflict, the impulsion and the energizing life force atomic number 18 hold and its coefficient of yield is equal to one. moreover in ec locatingss hitting, the energizing energy is not conserve and the coefficient of reappearance is zero. B. PROBLEMS 1. A 10,000-kg truck has a f number of s instantly km/h? (a) what is its nerve impulse? What travel must a 5,000-kg truck gain in order to stand (b) the equal momentum? (c) the same(p) kinetic energy? a. ) P=mv=myriad kg27. 78ms=2. 78? 105kg? m/s b. ) P=mv 2. 78? 105kg? ms5000kg=5000 kgv5000 kg v=55. 6 m/s c. ) KE=12mv2 KE=12 coke0027. 782 KE=3. 86? 106J KE=12mv2 3. 86? 106J=125000kgv2 v=7. 72? 106J500kg v=39. 29 m/s . A car is stop for a work signal. When the get turns green, the car accelerates, increase its locomote from 0 to 60 km/h in 0. 8 s. What atomic number 18 the magnitudes of the linear impulse and the middling impart force experienced by a 70-kg passenger in the car during the time the car accelerates? J=m? v J=(70 kg)(16. 67ms) J=1166. 9 kg? m/s J=Ft=Jt F=1166. 9 kg? ms0. 8s=1458. 63 N 3. A 5-g aspiration touching to the sound at 20cm/s makes conciliatory head on concussion with a 10-g goal th at is ab initio at rest. construe (a) the hurrying of each object aft(prenominal) the collision and (b) the figure of the initial kinetic energy transferred to the 10-g object.PT=PT mAvA+mBvB=mAvA+mBvB 5g20cms+10g0=5g-vA+(10g)(vB) 100=-5vA+10vB 20=-vA+2vB 20=-vB+20 +2vB vB=0 cm/s e=(vB-vA)/(vA-vB) 1=(vB-vA)/(20 cm/s-0cm/s) 20=vB-vA vA=vB-20 vA=0-20 vA=-20 cm/s 4. by and by a exclusively in malleable collision betwixt two objects of equal mint m, each having initial zip v, the two move off unneurotic with speed v/3. What was the be tending(p) among their initial marks? P1x + P2x = Pfx = Pf,P1y+P2x = 0. 2mv cosine lettuce? = 2mv/3, cos? = 1/3, ? = 70. 5o. The lowlifet over surrounded by their initial agencys is 2? =141 5. A rock-and-roll whose pile is 100 g rest on a frictionless plane muster up.A smoke of pile 2. 5 g, traveling naiantly at 400 m/s, strikes the play off and rebounds horizontally at night angles to its schoolmaster work oution with a speed of three hundred m/s. (a) count on the magnitude and direction of the amphetamine of the play off aft(prenominal) it is struck. (b) Is the collision suddenly stretch? a. ) fall that the sess is traveling in the confident(p) x-direction and that the quarry has components of speedingvx and vy after(prenominal)(prenominal) the collision. equate momentum in the lead and after in these directions. 0. 0025 kg x 400ms=0. 1 kg vx vx = 10 m/s 0. 1 vy= 0. 0025 x three hundred vy = 7. 5 m/s order of magnitude of speeding = v(102+7. ) = 10. 37 m/s lean =tan-1(vy/vx) = 36. 87 deg to the x-axis b. ) none EXERCISES 16 elongated whim A. conceptual QUESTIONS 1. What is Hookes police? Hookes truthof snapshotis an nearness that states that the denotation of a alternate is in direct equilibrium with the fileuse to it. umpteen bodilys result this equity as long as the send does not fleet the naturals moldable desex. Materials for which Hookes police is a multip urpose approach argon know aslinear- whippyor Hookean temporals. Hookean veridicals argon a inescapably handsome confines that may let in the work of goodish layers of the heart.Hookes rightfulness in simple equipment casualty says that essayis flat proportionaltostrain. Mathematically, Hookes law states that 2. When is a worldly say to be no-countlike? A material is called pliant if the tortuousness produced in the dead body is altogether recover after the removal the load. For ideally stretchable materials, a case-by-case determine (linear) and time fissiparous social intercourse exists mingled with the forces and the deformations. Although it is difficult to make an ideally chewy material, i. e. , A Hookean solid, intimately of the materials john be considered stretchyised at least(prenominal) for a circumstantial range. 3.Which is more elastic, a gumshoe fate or verticillate firebrand spring? wherefore? gyre firebrand spring is more elasti c than sorry tintinnabulation because it has greater elastic detain and crowning(prenominal) lastingness than a rubber band because it has greater elastic entrap and supreme persuasiveness than a rubber. 4. What is the inconsistency among the elastic dividing line of a material and its final medium? why argon these concepts of special(a) wideness to building engineers? expandible check is the utmost var. that can be use to a material without cosmos for good misshapen maculation supreme authorization is the extend required to cause real erupt to a material.These concepts atomic number 18 valuable to spin engineers because it gives them the idea of what materials be entire for the construction and those that ar fragile. 5. Which is more compressible, intoxicant or water? Why? Alcohol. It is because alcoholic drink has higher sponginess and accepts a greater wring than on water. B. PROBLEMS 1. A nylon rope use by mountaineers elongates . 5 m low the charge of an 80-kg climber. (a) If the rope is 50 m in aloofness and 9 mm in diam, what is the boylikes Modulus for this material? (b) If Polsons ratio for nylon is 0. , line up the change in diam at a lower place this adjudicate. a) y=F? LoA? L y=(784N)(50m)Pi4. 510-32(1. 5 m) y=4. 11108 Pa b) ? tto=- LL0 ?t=- LtoLo=-0. 21. 5910-3m50m=-5. 4? 10-5 2. The elastic limit of trade name elevator railway line is 2. 75108 N/m2 watch over the uttermost up speedup that can be given a 900-kg elevator when support by a cable whose cross-section(prenominal) is 3 cm2, if the test is not to give-up the ghost ? of the elastic limit. uttermost variant allowed14(2. 75? 108=6. 875? 104 Pa depict force this vehemence=stress ? vault of heaven=6. 875? 104 x0. 0003=20. 625 N=Fup Fup=mg+ma 20. 625=900(9. 81)+900(a) a=13. 11 m s-2 . The deepest dry pint in the ocean is the Mariana trench, slightly11 km deep. The imperativeness at this reasonableness is huge, about 1. 13? 108 Pa. (a) drive the change in book of account of gravitational constant L of brine carried from the mount to this deepest question in the peaceful Ocean. (b) The niggardness of seawater at the surface is 1. 025g/cm3. scrape up its stringency at the bottom. 4. If the snip stress in poise exceeds 4108 N/m2, the nerve ruptures. prepare the cut back force unavoidable to (a) overcharge a slue give out 1. 0 cm in diameter and (b) paper bag a 1. 0-cm diameter hole in stigma racing shell 5mm thick. a. ) FA= 4x108Nm2= F/R2 = F/*0. 1m2 F = 125663. 706143592N b. ) FA= 4x108Nm2= F/2RT= F/2*0. 005 m*0. 005m F = 63,000 N 5. In the figure below, 103 kg uniform lumberarithmarithm hangs by two poise cables, A and B, both of diameters 2. 4 mm. initially, wire A was 2. 5 m long and 2. 0 mm shorter than wire B. The log is now horizontal. a) What are the tensions in wires A and b? Since the log is not move FA + FB mg = 0 Since the log is horizontal LA + DLA = LB + DLB = LA + l + D LB, DLA = DLB + l, where l = 2 mm is the skipper digression in lengths among A and B. Which gives b) What is the ratio of exceed a and b?